This word has many meanings. Can be used as a greeting, to show anger or whatever you want it to mean.

What's up nehh?
I am so mad...NEHH!!!
When you're happy:nehhhhhhhhhhhhhhhhh!!
When you're drunk: durr... neeehh neeehh.
To pick up a girl: How you doin' neehh?
when you're lost (like scott):nehh? nehh? nehh???????